Explain how 'wellbore trajectory optimization' can enhance geothermal energy production from fractured reservoirs.

Wellbore trajectory optimization is the process of carefully planning the path of a geothermal well to maximize its intersection with productive fractures in a fractured reservoir, thereby enhancing geothermal energy production. In fractured reservoirs, the majority of fluid flow occurs through natural fractures rather than through the rock matrix itself. Therefore, the key to efficient heat extraction is to intersect as many productive fractures as possible. A vertical well may only intersect a limited number of fractures, especially if the fractures are vertically oriented. Deviated or horizontal wells, on the other hand, can be strategically drilled to intersect a larger number of fractures, significantly increasing the well's productivity. Geological and geophysical data, such as seismic surveys, borehole imaging logs, and tracer tests, are used to map the location, orientation, and density of fractures in the reservoir. This information is then used to design the optimal wellbore trajectory. The well trajectory can be optimized to intersect the dominant fracture sets at a high angle, which maximizes the flow rate from each fracture. The trajectory can also be optimized to connect multiple isolated fracture zones, creating a more interconnected flow network. Wellbore trajectory optimization can also help to reduce the risk of drilling into unproductive or low-permeability zones. By carefully planning the well path, it is possible to avoid these zones and focus on the most productive areas of the reservoir. Advanced drilling techniques, such as rotary steerable systems and logging while drilling (LWD), are used to precisely control the wellbore trajectory and make adjustments as needed during drilling. Therefore, wellbore trajectory optimization is a crucial technique for enhancing geothermal energy production from fractured reservoirs by maximizing fracture intersection and improving fluid flow.